A quantitative innovation perspective on synergism and selectivity mechanism of mixed collectors in flotation

Abstract

Use of mixed collectors in froth flotation confirmed effective separation of minerals with better selectivity and synergistic effects. But the underlying interaction mechanism still keep vague and have not been interpreted clearly so far. This work proposed a quantitative perspective to account for experimental flotation behavior from active site calculation, which has not been involved in flotation areas yet. Specifically, the mineral site distributions of diaspore and kaolinite were quantitatively characterized through calculated collector (sodium oleate (NaOL) and benzohydroxamic acid (BHA)) adsorption intrinsic constants. The algorithm principle was radically different from common homogeneous solution system without electric double layer. Using collector adsorption constants, all the initial and adsorbed product sites were counted in any circumstances to compare with corresponding flotation tests. The results showed that the 5 % higher recovery of diaspore at NaOL/BHA = 9:1 was attributed with 2 % more adsorption sites occupied than a single NaOL when both doses were controlled at 5 × 10-4 mol/L. On the contrary for kaolinite, the overall coverage of collectors was much smaller, indicating its poor recovery. Despite 10 % NaOL replacement by BHA in mixed collectors, neither the adsorbed site content nor the flotation efficiency for kaolinite was facilitated finally. Therefore, the significant discrepancies in adsorptions and flotations between diaspore and kaolinite contribute to their separation with the better selectivity of mixed NaOL/BHA than individual NaOL. The method established in this study may draw further attention for complex collector adsorption to facilitate flotation development.